Telephone-exchange.



N0- a29,419. PATENTED AUG. 28, 1906. N. E. NORSTROM.

TELEPHONE EXCHANGE. APPLICATION FILED NOV.14,1903.

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N. E. NORSTR'OM. TELEPHONE EXCHANGE.

APPLICATION FILED NOV. 14. 190B.

PATENTED AUG. 28, 1906.

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W ITNE$5 Es "FIG 2 In NTO R f BY Hi5 HTTOIkNfYdM N0- 829,419. PATENTED AUG. 28, 1906.

N. E. NO RSTRU M.

TELEPHONE EXCHANGE. APPLIOATION FILED NOV. 14. 1603.

7 SHEETS-SHEET 3.

WMESSES INVENTOR BY HISQTTQRH No. 829,419. PATENTEDJAUG. 2a, 1906.

' B. NORSTROM.

TELEPHONE EXCHANGE. APPLICATION FILED NOV 14 1808 7 BHEETB-BHBBT l.

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WITNESSES Juvsuros Z z 5 BY mag-1W2! N. E. NORSTRDM. TELEPHONE EXUHANGE.

Arrmonlon FILED 170?.14, 1903.

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INVENTOR WITNssszs V T E 711M? Mum ewacm PATENTED AUG. 28, 1906.

N? E. NORSTROM. TELEPHONE EXCHANGE.

APPLIOATION I'ILED NOV.14, 1908.

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Gwouiw FigJO lnuenT (Z4 M UNITED STATES PATENT OFFICE.-

NILS EMEL NORSTROM. OF CHICAGO, ILLINOIS. ASSIGNOR, BY DIRECT AND MESNE ASSIGNM ECTS. OF ON E-HALF TO JOHN ANDERSON, OF

SALINA,

KANSAS, 'AND ONE-SIXTH TO GLOBE AUTOMATIC TELEPHONE COM- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE-EXCHANGE.

of Letters Patent.

Patented Aug. 28, 1906.

Original application filed May 31, 1900.Serla1No. 18,519. Divided and this application filed crember 14, 1903. Serial No. 181.138.

To all whom, it may concern.-

Be it known that I, NnLs EMEL NORSTROM, a citizenof the United States of America, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Im rovements in Telephone-Exchanges, of which the following is a specification. My invention relates to telephone exchanges, and more particularl to the'call mechanism by which a required 'station is selected, the present application being a division of my. ending application, Serial 'No. 18,519, filed ay 31,1900.

The object of my invention is to simplify the manual 0 eratlons and provide mechanism which wil insure the proper selection.

In carrying out my invention I arrange at each telephone-station an index oi" keyboard, which is set at the required selection, after which the total operation is performed by the subscriber turning a crank. The selection itself is done automatically. By having a keyboard or index which is set if there is any error in the proper selection the keyboard will indicate whether thefault lies with the subscriber or the apparatus.

In the accompanying drawings, Figure 1 is a front elevation of one of the telephoneboxes used at the local stations. Fig. 2 is a similar view with the front cover of the box removed. Fig. 3 is an inside view of the cover, showin the. parts attached thereto and some of t e parts that also a pear in Fig. 2-. Fig. 4 is a side elevation of the box with a side removed so that the interior mechanism may be shown. Fig. 5 is a horizontal section across the upper art of the telephonebox, showing some of the upper interior mechanism. Fig. 6 is a similar section on line .6 fi'of Fig. 3 showing someof the parts in the lower part of the box. Fig.- 7 is a detail in section of some of the gears shown. in Fi s. 2 and 6. Fig. 8 is a section on line .8 8 of Fig. 3; and Figs. 9 and 10 are diagrams showin the apparatus at two telephone-stations an: their connections to corresponding switching mechanisms at the central office.

On the front cover of the telephone-box L is arranged a slide M, which is vertically movable in guides M. In the said slide are a series of small holes M, which are numbered consecutively from 1 to any required number, accordin to the length of theslide M, which length is determined by the number of telephone-box. said holes required. On the lower front portion 1 of the slide M is a projection V, by. which the l vertical position of the slide M may be adjusted by hand. Adjacent to the projection or lug V is a pointer V, and on theiront face of the outer guides M are a series of graduations marked from 0 to 9, asillustrated in the lower right-hand portion of Fig. 1. At its lowest or normal position the pointer or indicator V points at the graduation marked 9. Inside of the tele hone-box is the ordinary enerator G, whic may be rotated in the orinary manner by crank G on the front of the On the crank-shaft of the enerator is a small gear G which is engage by a se mentof a larger gear G pivoted .to a brac et on the generator G.

Secured on a hub of the gear G is a ratchetwheel G and loosely supported on said hub between the ear G and ratchet G is a large gear G, whic engages a gear G on the armatureof said generator. Pivoted on the gear G is a pawl G", arranged to engage with the ratchet G, so that when said ratchet is turned in one direction said turning will cause a rotation of the gear G, and consequently of the armature of the generator. When, however, the crank is turned in an o posite direction, the ratchet-wheel G will pass under the pawl G", and as a consequence the armature of the generator will not be rotated. On the armature-shaft is a segment of a disk 46, on which there is a pin G, to which is connected a spring G tending to hold the armature of said generator in a given position. When the crank G is rotated'clockwise, the ratchet-wheel G" drives the gear G, which in turn drives the gear G", and conse uently the armature of the generator. If, not sufficient to generate a current, the tension of the spring G will accelerate the movement of the armature during the last half of owever, the speed of rotation is 5 the rotation to a speed sufficient to cause a eration is permitted by reason of the fact that when the crank is turned clockwise the ratchet-wheel G is driven as fast as the crank, but the gear G may move faster by the pawl G riding-over the ratchet-wheel 1f the tension ofthe-s ring G is suflicient to cause it 130.110 so; If, however, the rotation of the crank G by hand is of speed suflicient to cause a proper generation of a current, the

spring proper current to be generated. This accel- I00 G does not act to accelerate the no sgeed of the armature. The spring G" t erefore acts to stop the armature at a given position when the crank is not being rotated and also as to produce a certain required speed of the armature of the generator at a certain required. portion of its rotation.

Secured on the rear face of the disk' 46 is an insulated pin G, which in its normal position engages a contact-spring 70 and pushes it into electrical connection with another spring 69. When, however, the armature is rotated, the pin Gr passes out of engagement with the spring 70 and permits it to break its electrical connection with the spring 69. i Insulatingly secured tothe generator-frame is a contact-spring45, which is engaged by disk 46 at one portion of its rotation so as to make electrical connection between the two at that particular time, but'to break such electrical connection at other portions of the rotation.

.Pivoted on the front cover is a bellscrank lever M, which is engaged by pin G at one ceiver is hung upon the hook K the portion of the rotationof the armature of the generator. This engagement causes a vibration of the bell-crank lever M on its pivot. Secured at a suitable point on the cover of the tele hone-box is a lever M which carries a pawl I, adapted to en age a ratchet-bar M secured on slide M. be lever M is connected by a rod M to the bell-crank lever M,

,so that when the. lever M is enga ed by pin G the vibration of the lever M wi 1 cause the same vibration of the lever M the result of which is to cause the pawlfM to engage the ratchet M and move it u ward one tooth. Thepawl M serves to hol said ratchet'M and consequently the connected slide M, from a downward movement untillthe said awl M is released, as will hereinafter be described. On the pawl M is a bent wirel which engages a post M in such a manner that when the lever M is at its normal position, as shown in Fig. 3, the pawl M isout of enga ement with the ratchet M he receiver-hook K is secured to a shaft Kf, on which shaft is also secured an arm K, one end ofwhich carries a in K. Secured on a block at the side of tlie telephone-box and in the path of. the pin K isa bell-crank lever 66, the horizontal arm of which is flexible and .the' outer end of which has a curved lip of the same character as that illustrated in another similar piece in Fig. 8. This horizontal arm is so arranged that when the 11'2- in 3 will engage the upper edge of the hori zontal arm of 66and ress itdownward, while upon the. rising oft e book K the pin K will engage the curve' ii ,and press the horizontal arm to one side, t ereby passingthe horizontal arm without moving the vertical arm from its osition. Located at a convenient place in t e telephone-box is a bell-ringer Q, on the armature of which is an arm Q adapted to engage the end of a catch Q, that enon the shaft K is anot gages and holds the bell-crank arm 66 in the position shown in Fig. 2. Adjacent to the arm 66 is a contact-point 67. These parts are so arranged that upon the o eration of the bell-ringer Q the arm Q wil strike the catch Q, releasing it from t 1e arm 66, when said arm will be forced by the spring back into contact with the contact-point 67. If after this operation has taken place the receiver be hung upon the receiver-hook K, the in K will engage the upper portion of the orizontal arm of 66, pressing it downward, and thus pressing the vertical arm backso it will again be caught by the catch Q and be held away from the contact-point 67. On the otherend of the arm K are supported an insulated contact-s ring 76 and another coi1- tact-spring 74, which is in electrical connection with the arm K, and conse uently with the shaft K and the receiver-hodl K.

Adjacent to and in the path of the contactsprings 74 and 76 is a strip 73, having contact-points 73 and 73 at its two ends, as shown in Fig. 2. Midwa between the two contactoints on the m tallic stri 73 is an insulate contact-point 77. In ig. 2 the hook K and the contact-springs 74 and 76 are shown in'their midosition. When the receiver is on the hook the contact-sprin 74 is in the position in which 76 is shown, an 76 is in a position. above the contact-point on the upper end of 73. When the receiver is removed from the hook K, the contactspring 76 is in the osition of contact-spring 74, as shown in -ig. 2, and the contactspring 74 is below the contact-point on the lower end of 73. It will therefore be evident that in the movement of the receiver-hook from the upper extreme to the lower the contact-spring 76 will engage the contact-point 77, and at the same moment the contact-. spring 74 will engage the lower contact-point on the strip 73. In the passin downward of the receiver end' of the hook these springs will pass upward over these points, then pass out of connection with them into the position shown in Fig. 2, and following this the contact-spring 74 will engage the contact-point 77, while at the same tlme the contact-spring 76 will engage the ugper contact-point on the r 5 strip 73 after whic further movement will cause these strips to pass out of enga ement with the said contactoints. Also lbeat'elher metallic piece. having two arms nearly horizontal' d the 120 third arm K projecting upward. 1e of the horizontal arms of K is connected by G to an arm of the gear-segment Gkso that when the receiver isplaced u on the receiver-hook Kthe said segmentwill emoved so as to turn 1 2 5 the gear Gr and consequently the ratchetwheel G and the gear G, the result of which is to give the armature of the generator G two rotations. When'the receiver-hook K rises by reason of removing the receiver, the [30 se ment G 'rotates the gear G and ratchetdue to the falling of the slide M by gravity, wheel in the opposite direction, in which said pin will engage thecurwed part W of case the ratchet-wheel moves under the pawl 5 said bell-crank, pushing it outward and pass- G" and the armature is not rotated. It will i ing below it without otherwise disturbing 5 therefore be apparent that when the receiver I said bell-crank 43. Secured to a convenient 70 is placed upon the hook K the result is to lace on the lower ortion of the slide M is a give the enerator two rotations, inakin two racket V, to whic is secured an insulated electrica connections between 46 an g V.

while, on theotherhand, the risingof thehook l Secured to the bottom of the telephoneio K, due to the removing of the receiver, does i box and in the path of the plug V are two 7 2o zontal arm of the metallic piece K is pro- 5 the horizontal arm of which is flexible and The other end of the bell-crank 43 is arranged 45 of the arm K on t contact-springs and 39, so arranged that the plug V may enter between them and press them back. In their normal position the springs 25 and 39 are in contact with contact-points 90 and 23; but when the plug V enters between the said'springs 25 and 39 it will push them out of engagement with the contact-points 90 and 23 into electrical connection with the contact-points 24 and 40.

ese springs, their contact-points, and the plug V constitute a current-reversing switch, the use of which will appear in the description of the circuits hereinafter to be given. The location of the plug V with respect to the springs 25 and 39 andalso with res set to the pointer V on the front of the sli e and t e graduations on the guides adjacent thereto is suchthat the plug V emerges from between the springs 25 and 39 immediately after the pointer V 3 rises above the gradua- 5 tion marked 0.

The up er hole M in the slide M is so related to t e bell-crank 43 and to the movement of the plug V in the springs 25 and 39 that immediately upon the emergence of said plug from engagement between the springs 25 and 39 the pin V, if located in the upper hole M will engage the bell-crank 43 and shift it from connection with 42 to 57. These various parts are arranged for hundreds and i0 5 units. he ointer V and the graduations which are a jacent thereto represent himdreds, and the holes in. the slide represent units. For example, the position shown in Fig. 1 illustrates the keyboard or indicator no set for 930that is, the pointer V is set at 9 and pin V'Fis set at 30. In this position when the slide M is moved upward by virtue of rotations of the generator nine. electrical contacts will be made between 46 and 45 before the plug V emerges from between the springs 25 and 39, and following this there will be thirty contacts between 46 and 45 before the pin V" engages the bellcrank 43 and moves it Tom contactoint 42 to contact-point 57. If the slide M lie moved upward by hand, so that the-pointer V will be adjacent to some other graduation, then the number of contacts made before the plug V emerges from between the springs 25 and 39 will lie ('Ul respondingly reduced and will be e ual to not in any way affect the armature of the generator.

The segment (1 is so related to its movement that when the receiver-hook K is at its 1'5 lowest or at its highest position the segment is free from the gear G and consequently the said ear and the armature of the generator may e rotated without interfering with the segment G or the hook K. The other horivided with a rod M", which passes through a tailpiece on the holding-pawl M. On the rod M is an ad justing-nut M, which may be set at any reguired position. These parts 2 5 are so arrange that upon the descent of the hook K by reason of the receiver bein placed upon it t e rod M will descend so t at the nut thereon will engage the tailpiece on the pawl M thereby releasing said pawl from the 0 rack M so that said rack and the slide M to which it is connected may fall by gravity to its normal position.

Located on the cover of the telephone-box near its upper portion is a bell-crank lever 43,

in slide M. The end of the horizontal arm of the bell-crank 43 is provided with a lip W,

which is given a curve, as shown in Fig. 8.

so as to engage either of two contact-points 42 and 57, which are secured to the cover of the telephone-box. Onthe lower end of the bell-crank 43 is a in K, that lies in the path lie metallic iece K.

Secured near one corner 0 the telephonebox are two brackets V, in which is supported a vertical shaft or rod V Loosely mounted on the shaft V is an arm V, the free end of 50 which constitutes a pin adapted to be inserted into any one of the series of holes M in slide M. en the pin is thus inserted into one of the holes M it projects through so that when the slide M is inoved upward the 5 5 said pin will en a e the lower part of the horizontal arm 0 t e bell-crank 43, moving it upward and shifting the other arm from t e contact-point 42 to contact-point 57. hen the receiver is placed on the hook K,

60 the movement of the arm K engages the pin K on the bell-crank 43 and moves the said bell-crank from contact-point 57 to the 0011- the number indicated on the graduation. tact-po1 nt42. When thepmVpasses above the pin V" be placed ill some other hole the horizontal arm of the bell-crank 43,and than that numbered 30, ilunumber of 65 in the downward movement of the said pin, contacts made after the time of the plug V 1 0 is also made with sufficient resistance to leaving the springs 25 and '39 will be correspondingly greater or less according to the position in which the p1n V is laced.

The devices at the centra office do not form a part of the present application, but are illustrated diagrammatically for the purpose of showing the circuits over which electrical P, which are in electrical connection with the bar H, and other contact-makers P in connection with the bar H. The contactmakers are arranged in pairs and are movable over contact-points which are connected to different Wires of a bank of wires 91.

B represents a magnet used for selecting a particular pair of contact-makers, and A represents another magnet used for moving the selected pairof contact-makers over their contact-points.

The construction and operation of these parts are fully shown and described in the application from which this is a division.

here is a switching mechanism for each tele hone in the exchange, and adjacent to eac switching mechanism are magnets C and D. The magnet or relay C is an ordinary one arran ed to operate with a very light current ans is provided with two armatures which have their ends polarized, as shown at N and S, representing north and south poles of the magnetized armatures. It

revent short-circuiting a talking-circuit inc uding lines 32 and 34.

When a current from the generator is sent through the relay C in one direction, it attracts the armature which has its north end ad jacent to the pole of the relay, and when a current is sent in an opposite direction through the relay it attracts the armature which has its south end adjacent to the pole of the relay. Connected to those two armatures N and S of the relayC are two contactclosing devices, one of which is connected to the magnet B of the switch and the other of which is connected to the magnet A. It will therefore be a parent that if a current be sent through t e relay C in one direction an electrical connection will be made through with which a current may pass through the magnet B, while if a current be sent through the rela C in the opposite direction a contact wil be made by which an'electri'cal current may be made to pass through the mag-.

net A. There is located at a convenient place in the central oflice a battery X, from one side of which battery a wire 100 extends with branch connections to the frame 0 of the magnet C of each switch in the exchange. It is to this framed) that the armatures N and S are pivoted, so that when a current passes to the frame C it may pass through eithercontact-closiing device to either contactpoint 47 or 51, and thus to either magnet B or magnet A. From the other side of the battery X a wire 50 extends through the exchange with branches to ma nets B and A on each switch. The magnet is arranged to operate under a very light current'and has its armature D" adjusted very close to the pole of the magnet, and said armature is part of the electrical circuit which passes through the magnet D andthrough the contact poifn't 71. The talking eircu'it passes through the magnet D, but is notpowerful enough to'opcrate it. If, however, any other electric current-as, for example, a current from the generatorG-passes through themagnet D, it will be sufficiently "powerful to actuate such magnet and break the connection between D and 71, so that a current passing through the magnet D cannot ass by 'way of '1)" 6X- cept for a fraction 0 its duration. From contact-point 71 the wire extends to the bar or support H of the switch, and from the magnet D a wire 32 extends to a bindingpost 31 on the telephone-box of the telephone which belongs to that particular switch. From the bar or sup ort H of the switcha wire 34 extends to a bi d'm post 35, also on the same telep ne box. wire 34 there is a branc to the relay C, and from the relay C a connection 33 to the magnet-frame D. -The various contact-points in the tele hone-box, most of which have been descri ed and all of which will be apparent by examining the diagrams in Fig. 9, are connected up by wires in the manner illustrated in said d'ia am.

Assuming that a su criber wishes to call another subscriber, he first sets the pin V into a hole representing the number of units which are in the number representing'the subscriber whom he desires to call. He then removes his receiver and adjusts the slide M so that the pointer V is o osite the number of hundreds of the subscri erwhom he wishes to call. He then turns his crank G" until the bell rings. He then has electrical communication with the subscriber with whom he desires to talk and said subscriber has been duly notified. The operation of removing his receiver, setting his indicator, and turning the crank G are all the operations that he performs in calling any givensubscri'ber in the exchange. All the other 0 erations are automatic and are as follows: pon turning the crank of his generator said generator is mm the o 5 I TO not in electrical connection with any line ex- C and 47, when a current flows as follows:

X, 100, c, 47, 43, B, '49, 50, X.

The operation of the generator operates the ,relay C and causes impulses to be sent through B, which in turn selects a pair of contact-makers. This operation is continued until the plug V passes out of its engagement with the springs 25 and 39 after [1106 impulses representing hundreds have been sent to central, when said springs move into connection with the contact-points 23 and '90. When that occurs, the current then,

flows 26, 21, 22, 23, 39, 33, 37, K, 36, 35, 34,

C, 33, D D, 32, 31, 30, 29, 23, 27, 26, 25, 90,

40, 41, 42, 43,, 44, 45, 46, 20. This is an electrical impulse sent in an opposite direction through the relay C, which attracts thearmature S, making electrical connection with the contact-point 51, when a current flows as follows: from battery X, 100, C, S, 51, 52, A, 53, 50, X; This energizes magnet A and moves the contact-makers P and P upward step by'step to succeedin contact-points in rows of contact-points. Vhen the slide M has been moved upward far enough by repeated rotations of the generator 20 so that thirty impulses have been sent, the in V will engage the bell-crank 43 and s ift it from contact-point 42 to 57. Then the current from the generator is shifted from relay J to ground through a bell-ringing device as follows, Fig. 9: 20, 21, 22, 23, 39,38, 37, K, 36, 35, 34, H, P, to the selected contact-point 80, to the bank-wire 91, and along the connected wire to the branch 81, Fig. 11, therefrom to the bar H of the selected switch, 34, 35, 36, K, 54 (hook of called switch being down,) 55, 56, Q, ground at the called telephone to ground at calling telephone Q, 56, 55, 57, 43, 44, 45, 46, 20. This operates the ringer of both telephones, which operation causes the arm Q to release the catches'Q and permit the bell-cranks 66 to be moved into electrical connection with the contactpoints 67. The called subscriber removes iis receiver, when a primary circuit is as follows: Y, 58, 59, 60, 61, K, 62, Y. The secondary or talking circuit is as follows: 59, 63, 64, 65, 66, 67, 62, K, 36, 35, 34, H, ,P, 1.6 the selected contact-point, 80, 91, to 81, and H of the called switch, 34, 35, 36, K, 62, 67, 66, 65, 64, 59, 63, 69,70, 27, 23, 29, 3o, 31, 32, D, D, D, 71, II, 82, to the line 91, and thence back to 83 of the calling-switch P, H, 71, D, D", D, 32, 31, 30, 29, 23, 27, 7o, 69, 63, 59.

To release, the subscribers 'han u their receivers. At the calling-station the d e scent of the receiver-hook causes the rod M to enage the tail of the pawl M and release it from the rack M, which permits the said rack and the slide M to drop again to their normal position. The descent of the hook also causes the arm K to engage the pin K 'and move the bell-crank 43 from contactpoint 57 back to its normal position into engagement: with the contact-point 42. The descent of the receiver-hook in moving the arm K also moves, through the connection G, the segment of a rack G which movement causes the generator-armature to make two rotations during the time when the hook is descending. At the same time during the descent of the hook and while the generator is being thus given two rotations the contactsprin s 74 and 76 make contact with 73 and 77, w ich first result, in a current as follows at the instant when the disk 46 engages the spring 45; 2 ,21, 22, 23, 72, 73, 74, K, 36, 35, 34, C, 33, D, D, 32, 31, 75, 76, 77, 73, 45, 46, 20. This current through attracts the armature S and makes an electrical circuit from battery K through the magnet A recisely as has been reviously described. mmedlately therea ter during the further descent of the hook and at the instant when the disk 46 engages the spring 45 in the second rotation of the generator this previously-described current through C is reversed as follows: {20, 21, 22, 23, 72, 73, 76, 75,31, 32, D, D 33, C, 34, 35, 36, K, 74, 77, 73, 45 46, 20. This reversal of the current through the relay C closes the connection of the magnet B when a current flows through that magnet from the battery X, as has been previously described.

The current through the magnet A immediately followed by a current through the magnet B is the electrical part of the operation which causes the switching mechanism to return to its normal position. Also in the descent of the receiver-hook the pin K engages the upper portion of the bell-crank 66, pushingit downward until said pin passes out of enga ement with said arm, which movement 0 the bell-crank causes it to be moved away from contact-point 67 and to be engaged and held by the catch Q".

It will be observed that the o erations of calling a subscriber arevery nine 1 simplified and are arranged so that there is asmallchance of error. By using a keyboard or indicator which is set for any required subscriber and which may be observed by the calling subscriber before he operates his generator the chances of error rising from selecting num bers during the process of calling is eliminated. As soon as he has set his indicator or keyboard and is satisfied that it is at the ri ht indication the only operation required 0 him is to turn the generator-crank G until the bell of his enerator rings. While turning the crank the slide M and the pin V are moving upward directly before his e es. By reason of the termination of the teet of the ratchet-bar M after the slide is moved up a certain distance, which would be equal to the greatest number of indicating-marks on the slide M, further rotations of the enerator will not raise the slide and the pin The upward movement of the said slide does not stop at the instant that the proper connec- .tion is made to the required telephone, but

roceeds upward until the end of the ratchet ii is reached or until the subscriber stops turning the crank C. The bell, however, begins to ring the instant the proper connection is made to the required subscriber, because upon the connection being made the pin V moves the bell-crank 43 from connection to its switch mechanism to connection with the bell-ringing device, so that the bell rings immediately. From this it will be apparent that if the subscriber in turning his crank observes that his indicating-slide M no longer advances u ward and the bell has not rung at the time w en it stops it will indicate to the calling subscriber that the one to whom he wishes to talk is busy. The reason for the bell not ringing is as follows: It will be observed by the diagram that a current passing to the bell-ringer Q must go by contact-point 54 through the hook'K or by contact-point 57 through the bell-crank 43. At the calling-telephone the subscriber has removed his receiver, so that the connection between K'and 54 is broken. He therefore can reach thebell-ringing device only when the bell-crank 43 is. moved to 57, which, as has been previously shown, occurs when the in V" reaches the said bell-crank. In the cal ed telephone the bell-crank 43 is not moved, but the subscribers receiver-hook is down in its normal position, if he is not bus in which case a current passes to the calle subscriber through the receiver-hook. From this it will be seen that the instant a called subscriber removes his receiver he can no longer be and the bell-crank 66, that this connection is normally disen aged until operated or released by the bel -ringer. From this it will be apparent that as the calling subscriber cannot operate his bell-ringer when hemoves his switch to a telephone that is busy that this inability to operate his ringer prevents him from completing the talking-circuit at his own telephone between 66 and 67. The bell-crank 66 and contact-point 67, together 6 5 with the ringer Q, form what may be called a dred an non-interfering device, which in this case is purely mechanical, operated or brought into operation by an electrical device.

The arrangement of numbers on the keyboard or indicator, as illustrated in Fi 1, is made for hundreds and an number 0 units up to ninety-nine, if desire It is not necessary, however, that the division between units and hundreds be in this particular form. For example, if the limit number of the telephones in the exchange is six huntwentydive, there may be six graduations for hundreds and ninety-nine graduations for the units, in which case the greatest number of contacts made for any selection would be six plus ninety-nine, which is one hundred and five contacts as the greatest number. There might, however, be ten graduations for the hundreds and sixty-three graduations in the units, in which case there would be as the greatest number of contacts made ten plus'sixty-three, equals seventy-three contacts. By making twenty-five graduations in the hundred and twenty-fivc'grad-uations in the units there would be also a combination of six hundred and twenty-five telephones; but the greatest number of contacts made would be'twenty-five plus twenty-five, equals fifty.

What I claim is 1. The combination with a generator, means for o eratin it, means for causing electrical impu see to e sent: by said generator at certain specified oints in its rotations, and a circuit over w ich impulses are sent, of an indicator, connections from said generator to said indicator for causing a movement of the indicator for each electrical impulse sent by said generator, means for setting said indicator for any required number of impulses, and means whereby upon the completion of the number of impulses for which said indicator was set, said indicator will cause succeeding impulses to be sent over said circuit in a reverse direction,

2. The combination with an electrical generator, means for operating it, means for causing electrical impulses to be sent by said generator at certain specifiedpoints in its rotations, and two circuits over which the imulses may be sent, of an indicator, means or setting said indicator for any required number of impulses sent over one of said circuits in one direction and any required numher in the opposite, direction over the same circuit, means whereby said indicator will control such impulses so as to cause their number and direction to correspond to the number and direction for which said indicator was set, and means whereby upon the completion of the totalnumber of required impulses said indicator will cause succeeding impulses to be sent over the other circuit.

3. In a selectingdcvice for automatic telephone-exch anges a slide and guides therefor,

ICC

a series of numbers on the face of said slide, opposite each of which numbers is a suitable he 6, a pin or lug adapted to be inserted in any oneof sai holes, means for moving'said slide in, its guides, and a switch or circuitchangingidevice located in the path of a pin in any one of saidholes, said switch-being arranged to shift an electric current from one ceiver hoo circuit to another when engaged by said pin.

' 4. In a selecting device for automatic telephone-exchanges, a slide and guides therefor, a series of graduations located on one member and a pointer located on'the other member, means for set-tin said slide with the ointer at any require graduation, a device or sending a series of electrical impulses and a current-reversing .switch through which such impulses are sent, connections from the impulse-sending device to said slide for moving it one step for each impulse sent, and means whereby said slide will operate said current-reversing switch when the number of impulses sent corresponds to the graduation at which said pointer was set.

15. In a selecting'device for an automatic telephone-exchange, a slide and guide therefor, a pin or projection adapted to be con nected to, said slide at any one of a number of different positions,a switch adapted to shift an electrical current from one course to another when engaged by said pin, a current-reversing switch, a device connected to said slide for operating said current-reverser when said slide has been moved to a particular position, an electric circuit including the current-reverser and the first-mentioned switcli,a device for sending a series of electrical impulses over said circuit, and connections from said impulse-sending device to said slide for moving it, the movement of said slide operating first the currentsreverser and subsequently the first-mentioned switch.

r 6. In a selecting device for automatic telephone-exchanges, a vertically-movable slide, a pin adapted to be inserted at difierent positions in said slide, and a pivoting-support for said pin, said support being arranged 'to permit said pin to move with said slide.

7. In a selecting device for automatic telephone-exchanges, a slide and guides therefor, a projection on said slide by which it may be moved by hand to any position in its guides,

a ratchet and pawl by which itis held in any givenposition, a propclling-pawl, and means or operating said propel ing-pawl so as to move said slide.

8. The combination with a switching mechanism, a gpnerator, a bell-ringer, anda reof an indicating and controlling device, connections from the generator to said device for moving it to correspond to impulses sent by said generator, means whereby the movement of said device will control such impulses so that they will cause a requiredseries of movements of the switching means for closing said contact-making mechanism and then cause an operation of the bell-ringer, and means for causing said device to be returned to its normal position by a movement of the receiver'hook.

9. In aselecting device, an electrical gen-- erator, an electric CIICUIU and a contact-closin device so arranged that an electrical i111- u se will be sent over said circuit once durmg each rotation of the armature of said generator, means operated by the rotation of said enerator for reversing the direction of such impulses after a predetermined number have been sent in onedirection. 'means for shifting such impulses to adifie'rent course after a predetermined number have been sent in the reversed direction, and an adjust able indicator for controlling the numberof impulses sent in each direction over said electric circuit.

10. The combination with a generator for sending a continuous series-of im ulses, and an indicator for controlling the istribution of such series of impulses, of means. by which said indicator may be set by hand to varythe distribution of impulses, and means for causing an additional movement of said indicator by the operation of said generator.

'11. The combination with a generator for sending a continuous series of impulses, and an indicator for controlling such continuous series of impulses, of means for moving said indicator by the movement of said generator, and a current-reversing switch operated by the movement of said indicator.-

12. The combination with an electrical generator, means for rotating its armature by hand, and automatic means for accelerating the speed of the armature at one part of its rotation, of a contact-making device, and device by the rotation of the armature at ie time when it is automatically accelerated.

13. In a stationselecting device provided with means for sending a series of electrical impulses,-a switch arranged to automatically reverse the direction of such impulses after a predetermined number have been sent, a second switch arranged to automatically shift the impulses from one course to another at a predetermined point in the series, and means by which said device may be set so as to cause said switches to act at any desired points in the series.

14. The combination with an electrical generator for sendin a series of electrical impulses, and electrioa circuits over which such impulses may pass, of devices for controlling the direction and course of such impulses, and an adjustable indicator by which said devices may be setso as to automatically control the number'of such impulses in two directions over one of said courses.

15. The combination with an electrical generator for sending electrical impulses, and electrical circuits over which such impulses may pass, of devices for automatically dividing a continuous series of such impulses into three parts distinguished by the direction and course over which the pass, andan ad- "ustable indicator by'w'hic e set so that any desired number of such impulses will be in the first two parts and the remainder will be in thethird part.

16. The combinationwitha' generator and means for sendi electrical impulses there from, of a movdlfie indicator "ro'vided with means for controlling the distrib impulses, and means for'o crating said indicator bv the movement oi the generator.

17. The combination'with agenerator and means for sending a series of impulses there from, of automatically-operating devices for dividing said series of'impuls'es into'three parts, means bv which the dividing devices may be set so that the first division will be at a predetermined number of iinu'lses from the first impulse, and 'a second means by which the dividing devices may be set so that the second division will be at a redetermined number of impulses from the rst division 18. The combination with a generator and means for sendin a continuous series of electrical impulses t erefrom, of two switches adapted to divide said series of impulses at ution of such two oints, and means for operating said 1 switches successively by the movements of i said generator.

19. The combination with, a generator and 1 means for sending a series of electrlcal 1mr l divide 831d series of impulses at two points, an indicator adapted to operate said switches y in succession, and means for operating said J indicator from said generator. f 20. The combination with a telephone se- 1 lecting device ada ted to send a series of impulses, of a crank y which said selecting device is given a primary operation and a receiver-hook by which it is given a secondary operation,means by which upon giving said selecting device a primary operation the desired station of a telephone-exchan' will be automaticall selected and signa ed, and means by W ich upon givin said selecting device a secondary operation y a movement of the receiver-hook the devices used in selecting will be returned to their normal position.

Signed at Chicago, Illinois, this th day of October, 1903.

NILS EMEL NORSTRUM. Witnesses:

THOMAS HAWKES, WM. A. ROWLAND. 

